The correct option is C Stomach wall of mosquito
Sporogony is one of the sexual stages of the Plasmodium. The nucleus of the oocyst of Plasmodium divides repeatedly to form a large number of daughter nuclei. At the same time, the cytoplasm develops large vacuoles and forms numerous cytoplasmic masses. These cytoplasmic masses then elongate and a daughter nuclei migrates into each one of them. This phase of asexual multiplication is known as sporogony and it takes place in the stomach wall of mosquito. This stage is completed in about 10-21 days.
Thus, the correct answer is option C.